Constant amplitude fatigue test research on M20 high-strength bolts in grid structure with bolt–sphere joints

2016 ◽  
Vol 20 (10) ◽  
pp. 1466-1475 ◽  
Author(s):  
Xu Yang ◽  
Honggang Lei ◽  
Y Frank Chen

The grid structure with bolt–sphere joints is one type of large-span spatial structures. Due to small induced force, light weight, large stiffness, and good seismic performance, such structural system has been widely adopted in industrial plants with suspending cranes. The damage of the grid structure with bolt–sphere joints tends to occur at high-strength bolt joints, with fatigue fracture as the primary failure mode. The alternating and reciprocating action of the suspending crane will cause fatigue problems to the structural components of the grid structure, including rod, cone, sealing plate, bolted sphere, and high-strength bolt. The threads in high-strength bolt result in a significant stress concentration leading to bolt fatigue which is the key issue of fatigue failure. In this study, systematic constant amplitude fatigue tests were conducted for 18 M20 high-strength bolt made of 40Cr material using the developed efficient and smooth loading equipment combined with the Amsler fatigue testing machine, in which the tension condition of the high-strength bolt in the grid structure was simulated, simulation of high-strength bolt in tension works of grid structure. In addition, the signal-to-noise curve and the calculation method of constant amplitude fatigue for the high-strength bolt are proposed in grid structure with bolt–sphere joints.

2016 ◽  
Vol 851 ◽  
pp. 775-779
Author(s):  
Chao Zhang ◽  
Hong Gang Lei ◽  
Shao Jie Tian ◽  
Xu Yang

Under the suspended crane loading, the key to the fatigue of the grid structure with bolt-sphere joints is the fatigue of the higher strength bolt. By now, there are not any research reports about the fatigue properties of M27 higher strength bolt at home and abroad. With the aid of the fatigue-testing machine and the loading device, this paper will have 8 constant amplitude fatigue experiments on test-piece, and will get the S-N curve of the higher strength bolt. With the aid of the metallographic analysis, this paper studies the mechanism and influencing factors of the fatigue failure; and with the aid of the finite element software ABQUAS, it analyzes and gets the stress concentration factor of the M27 higher strength bolt, and verifies the position of the fatigue failure.


Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2041-2053
Author(s):  
Jinfeng Jiao ◽  
Zhanxiang Liu ◽  
Qi Guo ◽  
Yong Liu ◽  
Honggang Lei

2016 ◽  
Vol 17 ◽  
pp. 14-30 ◽  
Author(s):  
Okechukwu P. Nwachukwu ◽  
Alexander V. Gridasov ◽  
Ekaterina A. Gridasova

This review looks into the state of gigacycle fatigue behavior of some structural materials used in engineering works. Particular attention is given to the use of ultrasonic fatigue testing machine (USF-2000) due to its important role in conducting gigacycle fatigue tests. Gigacycle fatigue behavior of most materials used for very long life engineering applications is reviewed.Gigacycle fatigue behavior of magnesium alloys, aluminum alloys, titanium alloys, spheroid graphite cast iron, steels and nickel alloys are reviewed together with the examination of the most common material defects that initiate gigacycle fatigue failures in these materials. In addition, the stage-by-stage fatigue crack developments in the gigacycle regime are reviewed. This review is concluded by suggesting the directions for future works in gigacycle fatigue.


2017 ◽  
Vol 734 ◽  
pp. 194-201 ◽  
Author(s):  
Yutaka Konishi ◽  
Takamoto Itoh ◽  
Masao Sakane ◽  
Fumio Ogawa ◽  
Hideyuki Kanayama

This paper investigates the fatigue results in low cycle fatigue region obtained from a miniaturized specimen having a 6mm gage length, 3mm diameter and 55mm total length. Fatigue tests were performed for two type lead-free solders using horizontal-type electrical servo hydraulic push-pull fatigue testing machine. Materials employed were Sn-3.0Ag-0.5Cu and Sn-5Sb. The results from Sn-3.0Ag-0.5Cu were compared with those obtained using a bulk specimen in a previous study. Relationship between strain range and number of cycles to failure of the small-sized specimen agreed with those of the bulk specimens. The testing techniques are applicable to Sn-5Sb following the Manson-Coffin law. These results confirm that the testing technique proposed here, using small-sized specimen, is suitable to get fruitful fatigue data for lead-free solder compounds.


2014 ◽  
Vol 638-640 ◽  
pp. 309-312
Author(s):  
Yong Wang ◽  
Hao Wang ◽  
Jue Hui Xu ◽  
Shu Xun Zhang ◽  
Zhao Ping Feng ◽  
...  

As a important tension member, high strength bolts having crucial effect for bearing capacity of grid structure. Especially for in-service engineering, when high strength bolt tensile load doesn’t meet the standard requirements, how to determine the structure bearing capacity influence is particularly important. The article is aimed at the situation of the design review and analysis, through the bearing capacity reduction, reducing the high strength bolt bearing capacity, and the reduction of bearing capacity and the actual force are compared, to determine the safety of the structure. Through the question processing, provides a discussion for solving the similar problems.


Author(s):  
Naoki Osawa ◽  
Tetsuya Nakamura ◽  
Norio Yamamoto ◽  
Junji Sawamura

A new simple fatigue testing machine, which can carry out fast and low-cost fatigue tests of welded joints subject to wave with high frequency vibration, has been developed. This machine is designed for plate bending type fatigue tests, and wave load is applied by using motors with eccentric mass. Springing vibration is superimposed by attaching an additional vibrator to the test specimen, and whipping vibration is superimposed by an intermittent hammering. Fatigue tests which simulate springing and whipping by a conventional servo-type fatigue testing machines are very expensive and use a large amount of electricity. If one uses these conventional machines, it is difficult to simulate superimposed stress wave forms at high speed, and it takes long hours of testing to examine the high frequency effect. In contrast, it is found that fatigue tests can be carried out in fast, i.e. waves with 10Hz or higher frequency for out-of-plane gusset welded joint specimens with 12mm plate thickness by using the developed machine. The electricity to be used for fatigue tests could be minimal, for example one thousandth of that needed for conventional machines. These results demonstrate the superiority of the developed machine.


2007 ◽  
Vol 353-358 ◽  
pp. 142-145 ◽  
Author(s):  
Ki Weon Kang ◽  
Byeong Choon Goo ◽  
J.H. Kim ◽  
Heung Seob Kim ◽  
Jung Kyu Kim

This paper deals with the fatigue behavior and its statistical properties of SM490A steel at various temperatures, which is utilized in the railway vehicle. For these goals, the tensile ad fatigue tests were performed by using a servo-hydraulic fatigue testing machine at three temperatures: +20°C, -10°C and -40°C. The static strength and fatigue limits of SM490A steel were increased with decreasing of test temperature. The probabilistic properties of fatigue behavior are investigated by means of probabilistic stress-life (P-S-N) curve and they are well in conformance with the experimental results regardless of temperature. Also, based on P-S-N curves, the variation of fatigue life is investigated and as the temperature decreases, the variation of fatigue life increases moderately.


2021 ◽  
Vol 877 ◽  
pp. 49-54
Author(s):  
Lorenzo Maccioni ◽  
Lorenzo Fraccaroli ◽  
Yuri Borgianni ◽  
Franco Concli

On the one hand, many mechanical components manufactured through additive technologies are optimized in terms of stiffness/weight or strength/weight thanks to lattice structures. On the other hand, the high complexity of these components often impedes further finishing operations and, therefore, the fatigue strength can be compromised. The high surface to volume ratio together with the high roughness, typical of additive manufactured components, promote the crack nucleation. In this paper, the High-Cycle-Fatigue (HCF) behavior of the 17-4 PH stainless steel (SS) was characterized. Cylindrical samples, manufactured via Selective Laser Melting (SLM) with an EOS M280, were tested in the as-build condition through a STEPLab UD04 fatigue-testing machine. In particular, a preliminary quasi-static traction test was performed on a sample to obtain the yield strength (σY = 570 MPa) and the ultimate tensile strength (UTS = 1027 MPa). Fatigue tests were performed on samples at different stress levels in order to characterize the whole Stress-Number of cycles (S-N) curve (Wöhler diagram). More specifically, the stair-case method combined with the Dixon approach were exploited to calculate the fatigue limit (σF = 271 MPa). The obtained results were compared with those present in literature for the same material and they are coherent with previous researches


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